[PATCH v2] ring-buffer: Prevent inconsistent operation on cpu_buffer->resize_disabled

Bagas Sanjaya bagasdotme at gmail.com
Sun Apr 9 05:30:53 PDT 2023


On 4/9/23 09:46, Tze-nan Wu wrote:
> This issue can be reproduced by "echo 0 > trace" and hotplug cpu at the
> same time. After reproducing success, we can find out buffer_size_kb
> will not be functional anymore.
> 

Do you mean disabling tracing while hotplugging CPU? Or disabling both
tracing and hotplug CPU?

> This patch uses cpus_read_lock() to prevent cpu_online_mask being changed
> between two different "for_each_online_buffer_cpu".
> 

"Use cpu_read_lock() to prevent ..."

> Changes in v2:
>   Use cpus_read_lock() instead of copying cpu_online_mask at the entry of
>   function
> 

To resolve kernel test robot warnings ([1] and [2])? Or have they been fixed?

[1]: https://lore.kernel.org/stable/202304081615.eiaqpbV8-lkp@intel.com/
[2]: https://lore.kernel.org/stable/202304082051.Dp50upfS-lkp@intel.com/

Thanks.

-- 
An old man doll... just what I always wanted! - Clara




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